Ah I think I see what you’re getting at, but that’s not really how Ember works, at least in anything past 1.11 or so (or whenever the CLI debuted). I started with Ember about when the CLI was introduced so I don’t have any memories of manual app config but some others here may. Anyway, the way it works since the CLI is you have a project in the conventional ember structure, you manage your dependencies with npm/bower (including ember and ember data and all other ember packages, this is where the versioning comes in), and then when you build with the CLI it smashes all of the dependency code together into vendor.js and the app code into app.js and then includes them in the generated index.html. So you’re never referencing the ember and ember data source files directly, you’re compiling them into your app when you build.
If the project you’ve inherited is pre-CLI you’ll want to migrate it to a CLI project and then upgrade from there. But honestly you may want to evaluate just rewriting it in modern Ember at this point. It really depends on how big and complex the app is. If it’s not huge it might actually just be faster to start fresh and copy paste CSS and bits of js here and there like your model attributes, etc.